1. Field of the Invention
The present invention relates to vascular transplants, to harvesting of vascular material for transplanting and for devices, materials and methods for the treatment of post-operative regions and cavities formed in the harvesting of vascular material to reduce post-operative complications.
2. Background of the Art
Post-surgical complications are a significant source of morbidity and mortality, and healthcare expenditure. For cardiac surgery, approximately one million patients undergo such every year, and approximately one in six develops a serious major organ complication relating to the heart, brain, kidney, GI tract and lung (Mangano, et al., 1997, J. Intensive Care Med. 12:148-160). Yet despite numerous advances in monitoring and technique, no drug has been shown to reduce or prevent these complications. The preoccupation has been with bleeding, and drugs are now used to prevent such. However, drugs which inhibit bleeding generally cause thrombosis, and therefore may induce ischemia and irreversible organ injury (Cosgrove, et al., 1992, Ann. Thorac. Surg. 54: 1031-36).
For noncardiac surgery, approximately 250 million patients undergo such every year, and approximately four percent develop a serious major organ complication relating to the heart. As well, concerns for bleeding predominate, and drugs preventing thrombosis (anti-platelet, anti-clotting) are virtually contraindicated (Eagle, et al, 1999, JACC 34:1262-1347; Pearson, et al, 1994, Circulation 90:3125-33; Baumgartner, et al., 1994, Johns Hopkins Manual of Surgical Care, Mosby Yearbook, St. Louis). However, for both cardiac and noncardiac surgery, marked excitotoxic and inflammatory responses occur for days after surgery, if not months after surgery. Such markedly exaggerated responses are associated with platelet and clotting factor activation, which may precipitate thrombosis.
Although recognized as a possibility, such agents are relatively—and in some cases (fibrinolytics), absolutely—contra-indicated because of fear of excessive hemorrhage at the surgical site, as well as at other sites. Further, some believe—especially after cardiac surgery—that platelet and clotting factor function are depressed after surgery, so that thrombosis is not an issue. Thus, no effort has been made to investigate the use of anti-clotting agents immediately following surgery.
Finally, perioperative events manifest over six to eight months or longer; thus, continuation of use of such anti-clotting agents throughout the in-hospital, and then post-discharge course, is rational.
Many individuals suffer from circulatory disease caused by a progressive blockage of the blood vessels that perfuse the heart and other major organs. More severe blockage of blood vessels in such individuals often leads to hypertension, ischemic injury, stroke, or myocardial infarction. Atherosclerotic lesions, which limit or obstruct coronary blood flow, are the major cause of ischemic heart disease. Percutaneous transluminal coronary angioplasty is a medical procedure whose purpose is to increase blood flow through an artery. Percutaneous transluminal coronary angioplasty is the predominant treatment for coronary vessel stenosis. The increasing use of this procedure is attributable to its relatively high success rate and its minimal invasiveness compared with coronary bypass surgery. A limitation associated with percutaneous transluminal coronary angioplasty is the abrupt closure of the vessel, which may occur immediately after the procedure and restenosis, which occurs gradually following the procedure. Additionally, restenosis is a chronic problem in patients who have undergone saphenous vein bypass grafting. The mechanism of acute occlusion appears to involve several factors and may result from vascular recoil with resultant closure of the artery and/or deposition of blood platelets and fibrin along the damaged length of the newly opened blood vessel.
Restenosis after percutaneous transluminal coronary angioplasty is a more gradual process initiated by vascular injury. Multiple processes, including thrombosis, inflammation, growth factor and cytokine release, cell proliferation, cell migration and extracellular matrix synthesis each contribute to the restenotic process.
While the exact mechanism of restenosis is not completely understood, the general aspects of the restenosis process have been identified. In the normal arterial wall, smooth muscle cells proliferate at a low rate, approximately less than 0.1 percent per day. Smooth muscle cells in the vessel walls exist in a contractile phenotype characterized by eighty to ninety percent of the cell cytoplasmic volume occupied with the contractile apparatus. Endoplasmic reticulum, Golgi, and free ribosomes are few and are located in the perinuclear region. Extracellular matrix surrounds the smooth muscle cells and is rich in heparin-like glycosylaminoglycans, which are believed to be responsible for maintaining smooth muscle cells in the contractile phenotypic state.
Published US Patent Application 20070098753 (Falotico) describes the use of coating agents on implements to prevent post-surgery effects causing inflammation and clotting.
Published US Patent Application 2007/0128181 provides methods of preventing or reducing post-surgical morbidity and mortality. Significantly, the prevention or reduction of post-surgical morbidity and mortality can extend beyond hospitalization. In certain aspects, the methods comprise the perioperative and long-term administration of a blood clotting inhibitor to prevent or reduce post-surgical complications. The blood clotting inhibitor can be administered perioperatively, that is, prior to, during and/or after surgery and after hospital discharge, for example, six months, one year or longer.
Healthy blood vessels are typically harvested to repair damaged vessels in other more critical parts of a human circulatory system. In particular, the saphenous vein is harvested from a patient's leg and utilized in bypass surgery where damaged and blocked arteries of the heart region of the patient are bypassed with the healthy blood vessel harvested.
Typically, the surgeon will harvest an appropriate length of the leg vessel requiring that the vessel be safely separated from side branch vessels and leg tissue, followed by an appropriate dissection of the end of the harvested vessel. In early surgery of this type, incisions were made along the length of the saphenous vessel to be harvested which was then dissected from the surrounding tissue. More modern surgical techniques have been developed and are utilizing a broad variety of vessel harvesting instruments and apparatus which greatly reduce the trauma to the patient. The following U.S. patents appear to represent at least a substantial portion of this more modern vessel harvesting technology.
Conventional deployment systems used to place medicaments in wound channels are described in Suzuki U.S. Pat. No. 6,475,177. These systems rely on syringe-like configurations in which the piston is held in place by a rigid rod. This design results in a rigid, inflexible device since the rod-piston assembly must support the compressive forces generated as the outer tube is deployed.
U.S. Pat. No. 6,660,016 to Lindsay discloses an endoscopic apparatus for harvesting blood vessels including an endoscopic barrel with a plurality of lumens, a handle disposed at a proximal end of the barrel and at lest one member for dissecting and cauterizing a blood vessel. An invention related to devices and methods for removing veins is taught by Spitz in U.S. Pat. No. 6,352,544.
David, et al., in U.S. Pat. No. 6,241,740 teaches a system and medical device for endoscopically ligating and cutting a body vessel, the improvements including a hinged jaw, an improved delivery system of a ligating clip and a rotating cutting instrument. A surgical instrument comprising an elongated hollow shaft having a longitudinal axis, a lumen, and an optical penetrating tip having a cylindrical portion attached to the distal end of the hollow shaft is taught by Kolata, et al. in U.S. Pat. No. 6,206,823.
U.S. Pat. No. 6,193,653 to Evans, et al. discloses methods and devices for harvesting vessels comprising a shaft having a handle mounted on one end and a dissecting tip on the other end. A light source is further optionally included and methods for transilluminating a vessel, dissecting the vessel, transecting the vessel and removing the vessel from the body are disclosed.
A method and apparatus for the minimally invasive harvesting of veins is taught by Ginn, et al. in U.S. Pat. No. 6,022,313 and devices and methods for minimally invasive harvesting of a vessel are shown in U.S. Pat. No. 5,913,866. U.S. Pat. No. 6,019,771 to Bennett, et al. teaches similar devices and methods as Ginn, et al. and we note that these three patents have been assigned to Cardiothoracic Systems, Inc.
U.S. Published Application US2005/0070940 to Genovesi, et al. teaches a method and device for harvesting vessels comprising a cannula-like device including means for identification, capture, manipulation, hemostasis and cleavage of branch vessels. That published application is a continuation application of U.S. Pat. No. 6,818,003 directed to a method and device for harvesting vessels. The harvesting cannula is configured as an elongated, hollow tube and comprised of three sections: a harvesting head, a tubular control segment and a sliding operation arm.
Another published application to Hess, et al., US 2003/0065348 and U.S. Pat. No. 6,656,176, disclose endoscopic vessel harvesting devices and methods. The method comprises locating the vessel, inserting the device through an incision, dissecting the vessel from the surrounding tissue and capturing vessels. The device comprises a headpiece having electrodes for ligation, a shaft having a lumen, and a vessel capturing means.
Other published applications and issued patents are known to applicant as follows: U.S. Pat. No. 6,527,786 to Davis, et al.; U.S. Pat. No. 6,679,892 to Guido, et al.; U.S. Pat. No. 6,464,708 to Higuma, et al.; U.S. Pat. No. 6,464,685 to Suzuki, et al.; U.S. Pat. No. 5,695,514 to Chin; U.S. Pat. No. 5,569,291 to Pirvitera, et al.; U.S. Pat. No. 6,004,335 to Vaitekunas, et al.; U.S. Pat. No. 6,375,635 to Moutafis, et al.; U.S. Pat. No. 6,214,028 to Yoon, et al.; U.S. Pat. No. 6,149,659 to Ahmed; U.S. Pat. No. 6,143,005 to Yoon, et al.; U.S. Pat. No. 6,099,535 to Lamport, et al.; U.S. Pat. No. 6,074,402 to Peifer, et al.; U.S. Pat. No. 6,007,551 to Peifer, et al.; U.S. Pat. No. 6,730,101 to Peifer, et al.; U.S. Pat. No. 6,565,578 to Peifer, et al.; U.S. Pat. No. 6,685,713 to Ahmed; U.S. Pat. No. 6,610,072 to Christy, et al.; U.S. Pat. No. 6,632,228 to Fortier, et al.; U.S. Pat. No. 6,607,542 to Wild; U.S. Publ. US2004/0122458 to Opie, et al.; U.S. Publ. US2005/0004586 to Suval; U.S. Publ. US2004/0204725 to Bayer; and U.S. Publ. US2005/0096677 to Wellman, et al.
As can be seen from a review of this technology, the implications of post-operative stress and collateral damage to tissue and residual effects from the surgery can have serious effects. The present technology attempts to reduce the post-operative effects from vascular harvesting such as veinous or arterial harvesting for transplantation, especially intrapatient transplant of vascular material.